arm,sim: fix context switch stats dumps for ARM64/Linux

32bit and 64bit Linux have different arguments passed to the
__switch_to() function that gem5 hooks into in order to collect context
switch statistics. 64bit Linux provides the task_struct pointer to the
next task that will be switched to, which means we don't have to look
up the task_struct from thread_info as we do in 32bit ARM Linux.

This patch adds a second set of accessors to ThreadInfo to extract
details such as the pid, tgid, task name, etc., directly from a
task_struct. The existing accessors maintain their existing behavior by
first looking up the task_struct and then calling these new accessors.

A 64-bit variant of the DumpStatsPCEvent class is added that uses these
new accessors to get the task details for the context switch dumps
directly from the task_struct passed to __switch_to().

Change-Id: I63c4b3e1ad64446751a91f6340901d5180d7382d
Reviewed-on: https://gem5-review.googlesource.com/2640
Reviewed-by: Curtis Dunham <curtis.dunham@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Pau Cabre <pau.cabre@metempsy.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/src/arch/arm/linux/system.hh b/src/arch/arm/linux/system.hh
index 709776ffc..247ebae13 100644
--- a/src/arch/arm/linux/system.hh
+++ b/src/arch/arm/linux/system.hh
@@ -132,6 +132,20 @@ class DumpStatsPCEvent : public PCEvent
     {}
 
     virtual void process(ThreadContext* tc);
+  protected:
+    virtual void getTaskDetails(ThreadContext *tc, uint32_t &pid,
+            uint32_t &tgid, std::string &next_task_str, int32_t &mm);
+
+};
+
+class DumpStatsPCEvent64 : public DumpStatsPCEvent {
+  public:
+    DumpStatsPCEvent64(PCEventQueue *q, const std::string &desc, Addr addr)
+        : DumpStatsPCEvent(q, desc, addr)
+    {}
+  private:
+    void getTaskDetails(ThreadContext *tc, uint32_t &pid, uint32_t &tgid,
+                        std::string &next_task_str, int32_t &mm) override;
 };